Conventionally, it is typical to stun poultry with an electrical shock, then thereafter bleed, scald, defeather, eviscerate, cool, and age at low temperatures for extended periods. In the conventional method, the carcass is usually scolded to make the removal of feathers easier. Next, the carcass is defeathered, and then eviscerated. As there is a fear that the carcass becomes deteriorated during succeeding elongated processing scheme, its temperature at this point is reduced to about 4.4° C., typically by chilling the carcass in an ice or cold water bath. The chilled carcass is then aged at this low temperature for an extended period, for example, on the order of about 4 to 12 hours, to provide the required degree of tenderness and organoleptic quality.
After the low temperature aging process, the carcass is drained and cooked. However, the time required to age the carcass from the evisceration to cooking is about 4 hours to half a day in the case of poultry carcass, and 7 to 10 days or more in the case of large carcasses, such as those of pigs and cows. Such an extended aging period may cause a great problem from the hygiene and operation viewpoint.
According to the method for processing poultry disclosed in U.S. Pat. No. 4,675,947, a live poultry bird is slaughtered without applying electrical energy, the resulting carcass is scalded, then the carcass is held in a warm, humid atmosphere at a temperature approximately equal to the normal temperature of the live bird before defeathering, and then the carcass is eviscerated. During while the carcass is held in the warm, humid atmosphere, intermittent electrical stimulation is applied to the carcass for a period sufficient to render the poultry meat tender upon subsequent cooking without the need for an extended, low temperature aging period. This method eliminates the low temperature aging, which requires an extended period, and a solution containing phosphate salts and sodium chloride is introduced to the carcass or component parts thereof to further improve tenderness.
However, it is ideal to evade deposition of phosphate salts and sodium chloride in natural food. Thus, there remains a need to greatly reduce the time period required for the aging of carcasses in comparison with conventional processing apparatuses and methods. There also remains a need to reduce viable cell count on the carcasses before cooking.